Question

Suppose you increase your walking speed from 5 m/s to 15 m/s in a period of 1 s. What is your acceleration?

Answer 1

The definition of accelerations is the change of speed by unit of time

change in speed Δv
=> acceleration = -------------------------- = ------
time elapsed Δt

[15 m/s - 5m/s]
=> acceleration = ----------------------- = [10 m/s] / 1 s = 10m/s^2

Answer: 10 m/s^2
1s

Answer 2

Using the kinematics equation vf = vi + at we plug in all known values 15 = 5 + a*1 solving for a we get 10m/s^2